1. Field of the Invention
The present invention relates to an image processing apparatus capable of generating an image signal for previewing the image output by an output device, and a method therefor.
2. Related Background Art
As a result of recent changes in the copying machines toward color image formation or more diversified functions, there is being encountered a drawback of increased time and cost as the user print the image on the recording sheet repeatedly before a desired color or a desired result of image edition is obtained. For avoiding such drawback, there are proposed copying machines with previewing function, for enabling confirmation of the image on a display such as a cathode ray tube, instead of image output on the recording sheet.
One of such apparatus employs a black-and-white liquid crystal display for displaying the read original image for the confirmation purpose, but, if the copying machine has full-color copying capability, the result of color adjustment or color conversion cannot be confirmed on such black-and-white liquid crystal display. For this reason there is recently proposed a previewing system in which the display device can also provide full-color display. FIG. 8 shows an example of such system, in which blocks 1-6 constitute a full-color copying apparatus while blocks 7-9 constitute a previewing system.
There are provided a sensor 1 for reading an original image and releasing R, G, B image data; an A/D converter 2 for effecting A/D conversion and shading correction; a sensor color correction circuit 3 for correcting the spectral characteristics of the sensor; a luminance/density conversion circuit 4 for converting luminance information into density information; an image editing circuit 5 for effecting various image editing operations; and a printer unit 6 for output of a full-color image based on the image data obtained by scanning the original image with the sensor 1 three or four times.
There are also provided a memory 8 for storing the R, G, B signals released from the sensor color correction circuit 3; and a cathode ray tube (CRT) 9 for providing a display based on the R, G, B signals stored in the memory 8.
Also a CPU 7, for arbitrarily processing the data in the memory 8, is connected to effect, by a software, a process equivalent to that of the editing circuit 5, thereby displaying a final image.
However the first-mentioned display method has been associated with a drawback that the full-color display merely indicates the read image but does not reflect the results of various image editing operations.
Also the second-mentioned display method has been associated with a drawback that the image processing in the copying apparatus, if all replaced by software process, requires an enormous amount of software, and, if more diversified functions are incorporated, the software process time correspondingly increases to a level inefficient in time and cost.